The broad aim of this project is to elucidate the environment of microbes in host cells and tissues. The specific aims are to identify, measure and evaluate the antimicrobial function of cationic proteins, peroxidase, proteinase, lysozyme, lactoferrin and other substances that phagocytes (especially polymorphonuclear leukocytes) may in the process of phagocytosis contribute to the intravacuolar or extracellular environment of bacteria. PMN from healthy persons and from persons with impaired resistance to infection, chronic granulomatosis disease or leukemia, for example, will be studied. Methods to be used include: 1) Assays of microbicidal activity in fractionated and in viable PMN. 2) Fractionation of cell organelles by velocity and isopycnic centrifugation in density gradients. 3) Purification of granule proteins by chromatography and electrophoresis. 4) Enzyme assay. 6) Immunodiffusion and radioimmunoassay. 7) Electron microscopy.